Use a bag such as this one to make your commute to work a bit easier. There are several ways to carry this bag, one of them being a detachable shoulder strap.
From OnBuy
School Professional Laptop Travel Carry Shoulder Bag for 13,14 Inch Apple/Windows Laptop/MacBook/Dell/HP/Lenovo with Smartphone Tech Accessories
Ecprof
135078 - A Port product- the Sydney is a toploading 13/14